A winch is typically a mechanical device used to pull in (or alternatively let out) a tensioned cable, wire, or cable. In its simplest form, a winch consists of a spool (that winds and unwinds) attached to a crank—which can either be hand or machine driven. Winches are often rigidly attached to an immobile object or heavy item such as a tow truck or steam shovel.
Winches have various applications, which are determined largely by their size and underlying design considerations. Many are used for recreational purposes, such as the towing of cars, boats or gliders. Others help retrieve recreational vehicles, such as pulling a boat onto a trailer. They are also used to accomplish the backstage mechanics necessary to move scenery in theatrical productions—such as to move large set pieces between performances. A new generation of winches have surfaced for use in snowboarding, wakeboarding and wakeskating designed to pull riders swiftly across a body of water or snow to simulate a riding experience normally supplied by a snow mobile, boat or wave runner.
Apart from recreation, winches also serve a very important role in the field of emergency rescue. Winches help remove debris and support recovery after various natural disasters such as floods, hurricanes, tornadoes, earthquakes and fires. This includes the lifting and removal of concrete partitions or other items which may have fallen on or trapped survivors of a natural disaster.
While various winches have been developed for purposes of emergency rescue, there exist numerous disadvantages and limitations in well known designs. For example, many winches today are add-on features to other motorized devices—typically chainsaws. One example of a chainsaw attachment is the “Lewis Winch.” While the device boasts a 150-foot cable capable of pulling a load of 4,000 pounds, the device has several drawbacks. Most notably is the fact it requires a significant amount of time to assemble the Lewis Winch onto a chainsaw. In addition to assembly time, the operator must stand and hold the chainsaw throttle to operate the device, which can place the operator in a compromised and dangerous position.
While some all-in-one gas powered winches have been developed, these current systems also have multiple drawbacks—most notably their limited capacity due to design configuration. As one example, Chicago Power Tools, Inc. offers a winch that includes a 2.5 horse-powered four-stroke engine-which can pull a load of only 3,000 pounds. As a second example, Portable Winch Company offers a Honda® powered four-stroke engine that can pull 2,500 pounds at 60 feet per minute. Despite their larger engines both of the aforementioned examples suffer from relatively low load capacities and the fact that four-stroke engines must be kept upright to operate, which is often impossible in a rescue or off road situation.
One of the key issues in rescue and recovery after an emergency is not only the ability to move large objects to search for and recover survivors—but also how to return these bulky objects to a resting place without risking the lives of still trapped or isolated survivors. For example, once a fallen concrete and steel beam is lifted to release a trapped survivor, it is often necessary to gently lower that fallen beam at the scene after the trapped victim is removed. A controlled release of such an object is important to ensure that the beam is not uncontrollably dropped, which may risk the safety of others still trapped.
Current winch designs, including the three currently offered gas-powered winches discussed above, fail to allow for the controlled release of the cable tension and to allow a user to have sufficient control during release of the load. In addition, current winch designs fail to allow for a compact design which affords a durable transmission system that includes a clutch assembly capable of allowing controlled release of loads.
Accordingly, there is a need for an efficient gas powered compact all-in-one winch design that allows for controlled release of the cable, along with the ability to vary the torque, pulling rate and load capacity of winch.